The present invention relates generally to an exercise and/or rehabilitation machine, and more particularly, is directed to an exercise and/or rehabilitation machine that bilaterally strengthens the upper, middle and lower posterior (truncal) extension muscles.
In normal childhood development, all infants pass though a motor development sequence that strengthens and reinforces the extension or posterior/dorsal muscles or posterior truncal extension muscles of the body. This serves multiple purposes.
First, it is neuromuscularly and neurophysiologically normal to counter the more primitive reflexive flexion posture that originates from birth. The flexion posture is represented by the anterior/ventral curled-up/fetal position at birth which lasts for the first few months of life. The onset of the extension/posterior/dorsal muscles, the pivot prone position, assists the infant in breaking out of the dominant primitive flexion posture. This allows the infant to strengthen the extensor musculature while simultaneously introducing rotation (rolling) in its normal development.
Second, the time spent in the extension movement pattern in normal development is so minor in relation to the total life span of the individual. The duration of the extension/pivot prone position in the infant is approximately four months. This four months is the only time in the individual's life when the posterior extension muscles are intrinsically developed.
Third, the extension pattern is strongest when the infant is most centrically aligned. This occurs when the infant is short in length and narrow in girth. As the infant/child grows in length and girth there is a reduction in the effectiveness of the nervous and muscular systems to maintain their central control. The support from the extension musculature is significantly reduced. This results in a less competent level of extensor strength in all functional activities of daily living, especially the upright/standing posture.
Thus the redirection of the primitive flexion pattern to extension, the small period of time spent in the extension pattern relative to the total life span, and the reduced efficacy of the extension pattern on the body as it matures in size and weight are all contributing factors in structural weakening of the individual. This lack of sufficient intrinsic extensor strengthening in infant development has a large negative effect on the strength of the lower back throughout an individual's life. Problems with lower back pain in adult life can be traced to the lack of complete preparation of the normal development process.
This is the result of adults suffering from lower back pain (LBP), which has become an epidemic, costing healthcare in the United States multiple millions of dollars as well as lost time in the workforce.
One way to augment or facilitate the temporally limited body extension development as an infant/child is to make a proper training device available.
For exercising a person's lower back muscles, it has been known to hold a person's legs while the person is positioned face down, and with the person's pelvic area supported on a supporting surface. The person bends or flexes his torso down to a position substantially perpendicular to his legs, and then raises his torso up to a position substantially parallel with his legs, and this exercise, known as a hyperextension exercise, is repeated as per accepted exercise training methods. Machines for performing this exercise are sold under the designation Glute/Ham machines. Examples of machines that can be used to perform this exercise are also disclosed in U.S. Pat. No. 5,205,804 and U.S. Pat. No. 4,391,443. This exercise can also be performed with a resistance force held at the person's upper back, as disclosed in U.S. Pat. No. 4,387,894. The entire disclosures of these patents are incorporated herein by reference.
More recently, a reverse hyperextension machine was developed by Louis J. Simmons, the subject matter of which is disclosed in U.S. Pat. No. 5,356,359 and U.S. Pat. No. 6,491,607 and the entire disclosures of which are incorporated herein by reference, which is the reverse of the aforementioned hyperextension machines. In this machine, the upper body is stabilized over the machine, and the lower body performs the work. Specifically, the legs are raised and lowered against a resistance force between a position perpendicular to the torso and a position parallel with the torso. These patents discuss the disadvantages of the hyperextension exercise, and seek to specifically avoid hyperextension of the lower back muscles, and thereby purposely direct or teach away from the hyperextension exercise.
The above hyperextension machines mostly involve the upper torso extensor musculature with minimum contribution from the lower torso extension musculature, while the reverse-hyperextension machines focus upon the lower torso extensor musculature with minimal contribution from the upper torso extensor musculature. However, no machines are known which utilize both upper torso extensor musculature and lower torso extension musculature simultaneously, that is, a total body extension machine.
A further problem with both the hyperextension and reverse hyperextension machines is that they require a person to lift a relatively large amount of weight to achieve beneficial results, which can also be harmful to the individual.
Another product that is sold under the trademark AB LOUNGE pivots at the center and extends past 180 degrees, with the person's upper body/torso and lower body/legs moving simultaneously. However, in this machine, the fulcrum where the hips of the person are positioned, moves during the exercise. The purpose of this machine is therefore to strengthen the anterior flexor muscles, that is, the abdominal muscles, rather than the posterior truncal extension.